The goal of the proposed research is to examine factors that influence the nutritional status of enterally fed critically ill patients. The specific research aims are: 1) to determine actual enteral nutrition intake compared to requirements, 2) to determine the percentage of patients who receive adequate nutritional intake, and, 3) to identify the influence of specific factors on the adequacy of enteral intake. A prospective, descriptive design will be used to address the specific aims. The study sample will consist of mechanically ventilated patients in the intensive care unit receiving enteral nutrition support. The resting energy expenditure of each patient will be measured using indirect calorimetry. The actual amount of enteral formula received will be compared to requirements determined by indirect calorimetry. All interruptions in continuous feeding will be documented. Examination of factors that influence adequacy of enteral intake will serve to advance an evidence-based approach to nutritional management of critically ill patients.